Patients with the diffuse forms of systemic lupus erythematosus nephritis are invited to enter a therapeutic trial. After modification of the plan in the course of the work, the three programs to which admissions continue are corticosteroids only, corticosteroids with cyclophosphamide and azathioprine both in low doses, and corticosteroids with intermittent intravenous cyclophosphamide. Regular follow-up of the 55 patients admitted continues.